A conventional touch panel includes a first substrate with a first conductive layer and a second substrate with a second conductive layer. The first and second substrates are spaced from each other by insulation spacers therebetween. When a user touches the touch panel, variation of voltage at the touched site is used for the calculation and determination of the position coordinates of the touched site by a microprocessor with known formulas.
The first and second conductive layers can be of a continuous planar structure, or can alternatively be of a structure comprised of a plurality of elongate conductive strips. For different structures of the conductive layers, the position coordinates of a touched site on the touch panel can be determined by using different methods of scanning and different formulas.
In the known techniques of using the structure comprised of elongate conductive strips, such as US Patent Publication No. 2005/0275634, which describes a resistive scanning touch panel, which can detect multiple touched sites by employing scanning techniques. The resistive scanning touch panel comprises a first conductive layer and a second conductive layer, of which the first conductive layer is comprised of a plurality of conductive strips running parallel in a first direction and the second conductive layer is comprised of a plurality of conductive strips running parallel in a second direction, and a controller. The operation principle of the patent is that the controller first applies a voltage to the conductive strips of the first conductive layer and simultaneously detects a voltage difference between opposite ends of the conductive strips of the second conductive layer to determine the coordinate of a touch point in the first direction. Then, a voltage is applied to the conductive strips of the second conductive layer and simultaneously, a voltage difference between opposite ends of the conductive strips of the first conductive layer is detected to determine the coordinate of the touch point in the second direction. These processes of applying voltage at one conductive layer and obtaining signal from the other conductive layer are repeatedly and alternately performed at the first and second conductive layers.
Another example is U.S. Pat. No. 5,181,030, which teaches detection of a sensing signal by applying a voltage to an end of a first conductive layer and grounding an opposite end to establish a potential gradient distribution and further applying a voltage to an end of each of elongate conductive strips of a second conductive layer and connecting an opposite end to a signal sensing circuit.
Further, Chinese Invention Publication CN1503195A discloses applying a drive voltage to an end of each of elongate conductive strips of a first conductive layer and connecting an end of each of elongate conductive strips of a second conductive layer to a scan detection circuit to perform signal scanning.